The surplus is caused by a lack of suitable males, implying a surplus of heterosexual females. Unless a lot of these females are bi, it's not much of a boost.
And I think now you are touching on the other part of her comment...
1. Sexuality - particularly with women, in my experience - is variable: hetro women can and do consider other women as viable sexual partners, even if they don't consider them long term partners;
2. The implication of a "surplus of hetero females" is flawed given that bi and homo females do, in fact, exist and aren't properly accounted for. Not every single female in that surplus is available to you. In fact, some of them are available exclusively to "themselves" if you were.
I'm not sure how that second point works wrt homo women, what do you mean by 'accounted for'?
also, not every single female in the surplus needs to be 'available', since it's a statistical implication. a surplus of hetero females correlates with a surplus of 'available' hetero females.
I think the overall meaning is that saying "Good news for guys then", while not a false statement, isn't a complete one either. "Good news for guys and lesbians" would be more accurate. "Good news for folks in the market for women" even more so.
I don't think she's in any way suggesting you're wrong, (and neither am I) she just wants you to remember that she exists as well and benefits from this too. I can't speak for her but I also see it as a slightly humorous addendum to your point.
I'll leave it to men to decide whether highly educated women being less likely to want to couple with available men is good for them. But I'm surprised anyone would assume it would be.
